Universidade Estadual de Londrina

About: Universidade Estadual de Londrina is a education organization based out in Londrina, Brazil. It is known for research contribution in the topics: Population & Toxoplasma gondii. The organization has 13052 authors who have published 19291 publications receiving 212123 citations.

Virulence Factors of Avian Escherichia coli

Abstract: A total of 45 strains of Escherichia coli isolates from chickens with colisepticemia were examined for virulence factors commonly found in pathogenic groups of E. coli. These strains were studied for the following: pathogenicity in 1-day-old chicks; toxin, hemolysin, and colicin production; cell invasiveness and adherence; hemagglutination for fimbriae detection; serum resistance; aerobactin production in iron-limited conditions; and plasmid content. The characteristics exhibited by virulent strains were invasion for HeLa and chicken fibroblast cells, serum resistance, colicin V, and aerobactin production. None of the isolates were toxigenic or positive in hemagglutination tests. The molecular genetic studies of the virulence factors by agarose electrophoresis showed that the plasmids of these strains are of high molecular weight.

Multifunctional toxins in snake venoms and therapeutic implications: From pain to hemorrhage and necrosis

Abstract: Animal venoms have evolved over millions of years for prey capture and defense from predators and rivals. Snake venoms, in particular, have evolved a wide diversity of peptides and proteins that induce harmful inflammatory and neurotoxic effects including severe pain and paralysis, hemotoxic effects, such as hemorrhage and coagulopathy, and cytotoxic/myotoxic effects, such as inflammation and necrosis. If untreated, many envenomings result in death or severe morbidity in humans and, despite advances in management, snakebite remains a major public health problem, particularly in developing countries. Consequently, the World Health Organization recently recognized snakebite as a neglected tropical disease that affects ~2.7 million p.a. The major protein classes found in snake venoms are phospholipases, metalloproteases, serine proteases, and three-finger peptides. The mechanisms of action and pharmacological properties of many snake venom toxins have been elucidated, revealing a complex multifunctional cocktail that can act synergistically to rapidly immobilize prey and deter predators. However, despite these advances many snake toxins remain to be structurally and pharmacologically characterized. In this review, the multifunctional features of the peptides and proteins found in snake venoms, as well as their evolutionary histories, are discussed with the view to identifying novel modes of action and improving snakebite treatments.